Has anyone had a failure of this type of relay that could have possibly issued an "open" command to a circuit breaker without receiving such an instruction ?
Is your REF545 an SCU (Switchbay Control Unit)? We have ABB's REF542 which is an SCU and have had one such incident in the past. Please give more details of REF545.
Thanks for the early reply. Yes, this REF 545 is providing back up protection to a circuit but it also controls the circuit breaker too. ie remote control and MMI local control.